Description of problem:
The version of the extension does not match gnome-shells version
$ cat /usr/share/gnome-shell/extensions/alternative-status-menu\@gnome-shell-extensions.gnome.org/metadata.json | grep version
"shell-version": [ "3.0.1" ],
which is wrong. It should be version 3.0.2, at least this is what
$ gnome-shell-extension-tool --create-extension
tells me. If I change it to version 3.0.2, then I have a permanent "Power Off ..." button as expected. Otherwise nothing happens at all.